Telecommunications networks such as asynchronous transfer mode (ATM) networks are used for the transfer of audio, video, and other data. ATM networks deliver data by routing data units such as ATM cells from a source to a destination through switches. Switches typically include multiple input/output (I/O) ports through which ATM cells are received and transmitted. The appropriate output port to which a received ATM cell is to be routed to and thereafter transmitted from is determined based upon an ATM cell header.
Oftentimes, the cell headers of ATM cells received on several different input port processors specify a single particular output port. The occurrence of such an event does not usually pose a problem unless the bandwidth capability of the connection through the output port is less than the sum of the bandwidth rates of the connections on the input port processors for an extended period of time. Such a problem is resolved by either discarding ATM cells which cannot be included within the allocated output bandwidth or asserting flow control back at the connection source.
A further problem exists, however, in that the discarding of ATM cells has heretofore not been evenly distributed among the several different input port processors. That is, ATM cells have been disproportionately discarded among the connections from the several different input port processors. Such can result in a corresponding disproportionate diminishment of data quality causing, for example, undesirable interruptions in audio and video data transmissions or other more serious damage to other types of data transmissions. Accordingly, it would be desirable to devise a scheme whereby the allocated output bandwidth of a connection at an output port is evenly distributed among sources for a connection from the several different input port processors in a multipoint-to-point switching scenario.